In your battle against the forces of the Burning Hells, it's a good idea to have allies. You can team up with other heroes in Diablo III quickly and easily, either with your friends or alongside other heroes in a public game.
Once you’ve logged into Diablo III, you’ll see the public games menu on your character selection page.
Clicking the "Public Games" button will allow you to choose which quest you’d like to play. Note that you can only choose to join a quest you’ve begun, regardless of how far along other players in your game are.
After you’ve hit the "Join a Game" button, you’ll be quickly matched up with other players on the same quest and within a similar level range. You can play with up to 3 other players (4 participants total) in a cooperative game.
If you’re already playing by yourself and you’d like to invite others to join your game, it’s simple. While playing Diablo III, you can make your game public by opening the Game Menu with "ESC" and choosing "Open Game to Public").
You can also ask people you know to accompany you on a quest. In-game, open your Social menu, find the friend you’d like to invite, and click the "Invite to Party" button next to their name. If they’re playing Diablo III, they’ll receive an invite, and if they accept it, they’ll enter your game.
Once you’re part of a party, you’ll have a few special tools at your disposal for interacting. The arrows and small window in the lower left corner of your screen show the location of your chat window. This window, which remains transparent unless you hold your mouse over it, is a log of your interactions in game.
This is where you’ll see messages you’ve typed to other players and any messages you've received. To send a player a message, you can highlight their name in your social window and click "Chat", or you can send them a message directly. After hitting "ENTER" or "RETURN" on your keyboard, you’ll see the
message you’re typing appear in your chat window.
Clicking on the gear icon in the chat window allows you initiate a private conversation with up to 99 other players. You can be in a different game than the people you’re chatting with.
Playing with others offers some significant advantages, but it also impacts gameplay in a few noteworthy ways.
When you’re in a party, you can see the health and current status of your party members in their portraits at the top of your screen. If you’d like to get right into the action with them, you can teleport instantly to the current location of your party members by clicking on their banners in town. Finally, you can trade items with other players by right-clicking on their portraits and choosing "Trade," which will bring up a trading window that will allow you to exchange items and gold.
"Loot" in groups is individualized: each player finds their own personal items and gold on the corpses of slain foes or inside chests. It's impossible to steal items another player finds.
Though you can form a party with up to three other players (for a total of four players), you can’t bring your followers along when you’re in a group with other people, no matter the size of your party.
Each player in a group shares the state of the game they’ve chosen to join. For example: if you’ve slain the Skeleton King with your character, but just joined a public game where your objective is to kill him, he’ll be alive again in this game, and any important story unlocks associated with his death (new areas unlocked, specific NPCs, etc.) won’t be available to you.
Most importantly, more players in a party also means stronger foes. With each addition to your party, the legions of the Burning Hells will grow more powerful. Be careful: although you have the might of several heroes at your side, you'll find that enemies you defeated easily in the past may require additional effort when you’re playing in a group.
Emotes are simple keyboard shortcuts you can use to quickly communicate with other players–they make your character talk, sharing crucial information like "follow" or "run." Commands are text shortcuts that you can use to manipulate chat channels or take advantage of parts of Diablo III’s interface.
To use an emote or command, simply type “/” (forward slash) followed by the text you see below. You can bind emotes (and some commands) to different keys in the Key Binding section of the Options menu.
Emotes that are unbound by default:
When you complete certain heroic tasks in Diablo III, you won’t just receive gold, treasure, or the satisfaction of spilling the blood of your enemies. You’ll also unlock an achievement, a measure of your prowess in gameplay.
Achievements are usually unlocked from important, unique, or challenging tasks, like killing a monster in a more difficult way, finishing an Act, or completing the game on a higher difficulty level. Each achievement you unlock is worth a certain number of points, so you can measure your current progress against all of the challenges in Diablo III.
If you want to see what you've accomplished or look for future challenges, check the in-game achievements menu (default key “Y”) for a full achievement list. Achievements are shared across the characters on your account; any achievement you unlock can be viewed with all of your characters.
Unlocking certain achievements will provide you with new patterns and accents for your banner, a battle standard that you can customize to show your accomplishments to other players in game.